- Chinese name
- Crab Nebula
- Foreign name
- Crab Nebula
- Alias
- M1 、 NGC 1952
- Classification
- Nebula and supernova remnants
- Discoverer
- John Bevis [13]
- Discovery time
- 1731 [13]
- surface temperature
- 11000 to 18000 ℃
- Apparent magnitude
- eight point four
- Absolute magnitude
- -Class 3
- Right ascension
- 5:34:31.94s
- Declination
- +22°00′52.2″
- Distance from ground
- 6500 light years
- Regulatory Bureau
- 11X7Ly
- Central stellar explosion
- 1054
Ancient Chinese records [15]
Crab Nebula In the early 20th century, an analysis of nebula photos taken at intervals of several years earlier showed that it was expanding. According to its expansion speed Backstepping It can be seen that the nebula began to be visible on the earth at least 7400 years ago (900 years plus the time when light spread from there to the earth about 6500 years, see above). And China astronomer The record in 1054 produced a bright star in the same area of the sky, which can be observed even in the daytime. Although the distance is very far, the guest star observed by the Chinese at that time can also be seen in the daytime, so it can only be Supernova 。 This is a kind of self nuclear fusion Has terminated and collapsed, causing explosion High quality fixed star. 
Crab Nebula The Crab Nebula is expansive Supernova The relic was observed and discovered by Chinese and Arab astronomers in 1054 AD. When the star explodes, it will leave a“ Pulsar ”Of high-density Stellar debris. The pulsar rotates at the speed of 30 times per second, but the pulsar's rotation speed gradually slows down as it continuously ejects particles and electric field wind. The main cosmic particles are electric particles X-ray and Gamma ray High energy Radiation Jets are accelerated as they pass through the Crab Nebula's magnetic field. But before that, researchers did not know exactly where these cosmic particles accelerated. university of southampton Researcher Tony Dean said that this kind of universe Particle acceleration The phenomenon usually occurs very close to pulsars. It is reported that Dean and his research colleagues are based on the European INTEGRAL satellite observed data In conclusion, this study shows that 46% of gamma ray ejections of pulsars appear polarization , accompanied by photons electromagnetic field Arranged in a common direction. U.S.A Aerospace game Goddard Space Flight Center David Thompson of Astrophysics It is a very high proportion of astronomical phenomenon, like this percentage The phenomenon of polarization means that the situation here is very good, and the internal magnetic field is very orderly. " Such an orderly magnetic field is usually considered to appear near the pulsar, and the magnetic field on the surface of the pulsar is more than Geomagnetic field 1 trillion times stronger. This kind of magnetic field is very like a bar magnet. Because it is very close to the pulsar, it emerges from one of the magnetic poles Magnetic field line It will bend to form a doughnut shape before it returns to other magnetic poles. Thompson told《 New scientist 》The magazine said, "Once the magnetic field leaves the pulsar, its situation becomes more complicated, because the magnetic field begins to split into small pieces and knots." This latest research result shows that the particle flow in the pulsar cosmic wind is being accelerated to approach the pulsar, and then the magnetic field becomes disordered and complex. Thompson said that the discovery was consistent with Theoretical prediction This prediction is difficult to observe. Only a few are applied to the polarization of X-ray and gamma ray wavelengths measuring method Can be realized. Italian University Trieste International Institute of Advanced Studies Annalis Seloti of Polarization direction It is very difficult, and the current test methods are not sensitive, and can not completely measure the polarization of distant objects. Thompson agreed with Sellotti's comments, saying, "This phenomenon is difficult to reproduce in another pulsar, because the Crab Nebula is very close to the Earth, only 6500 light-years away, which makes it relatively easy to detect. The Crab Nebula is all Astronomical researchers Our favorite astrophysics laboratory has studied and answered these simple questions. What we need to do is to conduct more complex research. This latest research has insight into the magnetic field as an "engine device" to accelerate particles, which will help researchers infer what power is driving more distant and dim celestial objects. Thompson said, "Pulsars and their surrounding regions are very extreme examples of astrophysics. What you know about how they work will help us understand particles acceleration And magnetic field. " [1] The Crab Nebula visible light There are a lot of oval filamentous structures around the diffuse blue Core area , up to 6 Angular minute , width up to 4 cm (by contrast, the diameter of the full moon is 30 cm) Apparent diameter One of the largest celestial bodies. From a three-dimensional perspective, the nebula is a long Ellipsoid [6] These filamentous structures are Predecessor star The residual composition of the atmosphere, mainly composed of ionized helium and hydrogen, also contains carbon, oxygen, nitrogen, iron, neon and sulfur. The temperature of these filamentous structures is generally between 11000 – 18000K, and their density is about 1300 particles per cubic centimeter. [7] Although the Crab Nebula is one of the focuses of astronomers, its distance error is still an unresolved problem due to the uncertainty of each estimation method. The consensus reached in 2008 is that its distance from the earth is 2.0 ± 0.5 Kilosecond gap (6.5 ± 1.6 thousand light years). The Crab Nebula is expanding at a speed of about 1500 km/s. [8] The analysis of the nebula photos that have been separated for several years shows that it is slowly expanding [9] , compare this angular expansion with Einstein shift This method can also estimate the distance from the nebula to the earth. In 1973, an analysis using a variety of different methods of ranging concluded that it is about 6300 light years away from the earth. According to its apparent diameter and distance, it can be calculated that its diameter is about 13 ± 3 light years. [10] Estimated nebular Total mass For estimated correspondence Supernova The quality of the predecessor star is crucial. The material (ions and Neutral gas Ejecta , mainly helium,) estimated mass up to 4.6 ± 1.8M ☉ [12] 
Crab Nebula Normally, the pulse radio sources in the universe only have one pair of magnetic poles - the North Pole and the South Pole. However, Tim Hankins and Gene Erek of the New Mexico Institute of Technology in the United States found that the traditional two pole theory could not explain the activity of the pulse radio source in the Crab Nebula. Hankins said that the magnetic field of radio source in the Crab Nebula was obviously distorted due to the interaction of multiple magnetic poles.
Scientists said that in the vast universe, the vast majority of pulsed radio sources only produce one pulse, and a few of them except one Main pulse There is also another secondary pulse -- the latter is called "intermediate pulse". Experts believe that each pulse will correspond to two magnetic poles, and their relationship is like a pair of inseparable friends. However, Hankins and Eric found that the pulsed radio source in the Crab Nebula is completely different - its main pulse is short and strong, and the "intermediate pulse" lasts for a long time, but its power is weak. In addition, the radio radiation emitted by this "intermediate pulse" is completely different from that of other pulsed radio sources. Another American scientist Paul Freer pointed out after analyzing the research results of Hankins and others that the radiation generated by the "intermediate pulse" found in the Crab Nebula is extremely special, and has never encountered a similar situation before.
According to the view put forward by Hankins, the cause of the "intermediate pulse" radiation anomaly may be the existence of the third magnetic pole. Perhaps, the third magnetic pole appeared during the formation of the pulsed radio source. As for how the above process develops, further research is needed.
Hankins added that the pulsed radio source in the Crab Nebula should also have a fourth magnetic pole - because all magnetic poles appear in pairs.
According to the official website of NASA, recently observatory One of the Crab Nebula was observed neutron star Releasing a large number of High-energy particle , its energy release The speed is 100000 times that of the sun. In about 1054 AD, humans could observe the death of a star in Taurus Supernova explosion 。 Today, nearly a thousand years later, people can still see the spectacular scene after the death of this star. After the supernova explosion, a kind of ultrahigh density object, namely neutron star, was produced explosive residue The area occupied is known as the Crab Nebula. This neutron star is radiating a large amount of High-energy particle , forming a storm of high-energy particles. Observations at NASA's Chandra X-ray Observatory data display This neutron star is like a huge cosmic dynamo. Hubble Space telescope and Spitzer Space Telescope They also participated in the observation. According to the three major Astronomical telescope The observed data finally form a "Crab Nebula" neutron star High-energy particle Composite of storms. The blue part in the picture is the X-ray image formed by the data of Chandra X-ray Observatory, and the yellow and red parts are taken by the Hubble Space Telescope optical image The purple part is the infrared image taken by Spitzer Space Telescope. Among them, the X-ray image is smaller than other images, because the X-ray emitted by extremely high-energy electrons is smaller than Low-energy electron Optical and infrared emission Ray energy The decay rate is much faster. For a long time, the Crab Nebula has been one of the most studied space objects by human beings. It has been regarded by scientists as the representative image of the universe. In the past decade, the Chandra X-ray Observatory has often cooperated with other telescopes to make joint observations of the Crab Nebula. [2]
China Tiangong No.2 The Crab Nebula has been observed for the first time in China Pulsar Of Pulse signal Orbit determination has promoted pulsar observation and navigation technological development 。 [14] 
